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Diffstat (limited to 'libstdc++/include/bits/gslice.h')
| -rw-r--r-- | libstdc++/include/bits/gslice.h | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/libstdc++/include/bits/gslice.h b/libstdc++/include/bits/gslice.h new file mode 100644 index 0000000..12bfc32 --- /dev/null +++ b/libstdc++/include/bits/gslice.h @@ -0,0 +1,170 @@ +// The template and inlines for the -*- C++ -*- gslice class. + +// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2004, 2005 +// Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 2, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING. If not, write to the Free +// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, +// USA. + +// As a special exception, you may use this file as part of a free software +// library without restriction. Specifically, if other files instantiate +// templates or use macros or inline functions from this file, or you compile +// this file and link it with other files to produce an executable, this +// file does not by itself cause the resulting executable to be covered by +// the GNU General Public License. This exception does not however +// invalidate any other reasons why the executable file might be covered by +// the GNU General Public License. + +/** @file gslice.h + * This is an internal header file, included by other library headers. + * You should not attempt to use it directly. + */ + +// Written by Gabriel Dos Reis <Gabriel.Dos-Reis@DPTMaths.ENS-Cachan.Fr> + +#ifndef _GSLICE_H +#define _GSLICE_H 1 + +#pragma GCC system_header + +_GLIBCXX_BEGIN_NAMESPACE(std) + + /** + * @brief Class defining multi-dimensional subset of an array. + * + * The slice class represents a multi-dimensional subset of an array, + * specified by three parameter sets: start offset, size array, and stride + * array. The start offset is the index of the first element of the array + * that is part of the subset. The size and stride array describe each + * dimension of the slice. Size is the number of elements in that + * dimension, and stride is the distance in the array between successive + * elements in that dimension. Each dimension's size and stride is taken + * to begin at an array element described by the previous dimension. The + * size array and stride array must be the same size. + * + * For example, if you have offset==3, stride[0]==11, size[1]==3, + * stride[1]==3, then slice[0,0]==array[3], slice[0,1]==array[6], + * slice[0,2]==array[9], slice[1,0]==array[14], slice[1,1]==array[17], + * slice[1,2]==array[20]. + */ + class gslice + { + public: + /// Construct an empty slice. + gslice (); + + /** + * @brief Construct a slice. + * + * Constructs a slice with as many dimensions as the length of the @a l + * and @a s arrays. + * + * @param o Offset in array of first element. + * @param l Array of dimension lengths. + * @param s Array of dimension strides between array elements. + */ + gslice(size_t, const valarray<size_t>&, const valarray<size_t>&); + + // XXX: the IS says the copy-ctor and copy-assignment operators are + // synthetized by the compiler but they are just unsuitable + // for a ref-counted semantic + /// Copy constructor. + gslice(const gslice&); + + /// Destructor. + ~gslice(); + + // XXX: See the note above. + /// Assignment operator. + gslice& operator=(const gslice&); + + /// Return array offset of first slice element. + size_t start() const; + + /// Return array of sizes of slice dimensions. + valarray<size_t> size() const; + + /// Return array of array strides for each dimension. + valarray<size_t> stride() const; + + private: + struct _Indexer + { + size_t _M_count; + size_t _M_start; + valarray<size_t> _M_size; + valarray<size_t> _M_stride; + valarray<size_t> _M_index; // Linear array of referenced indices + _Indexer(size_t, const valarray<size_t>&, + const valarray<size_t>&); + void + _M_increment_use() + { ++_M_count; } + + size_t + _M_decrement_use() + { return --_M_count; } + }; + + _Indexer* _M_index; + + template<typename _Tp> friend class valarray; + }; + + inline size_t + gslice::start () const + { return _M_index ? _M_index->_M_start : 0; } + + inline valarray<size_t> + gslice::size () const + { return _M_index ? _M_index->_M_size : valarray<size_t>(); } + + inline valarray<size_t> + gslice::stride () const + { return _M_index ? _M_index->_M_stride : valarray<size_t>(); } + + inline gslice::gslice () : _M_index(0) {} + + inline + gslice::gslice(size_t __o, const valarray<size_t>& __l, + const valarray<size_t>& __s) + : _M_index(new gslice::_Indexer(__o, __l, __s)) {} + + inline + gslice::gslice(const gslice& __g) : _M_index(__g._M_index) + { if (_M_index) _M_index->_M_increment_use(); } + + inline + gslice::~gslice() + { + if (_M_index && _M_index->_M_decrement_use() == 0) + delete _M_index; + } + + inline gslice& + gslice::operator= (const gslice& __g) + { + if (__g._M_index) + __g._M_index->_M_increment_use(); + if (_M_index && _M_index->_M_decrement_use() == 0) + delete _M_index; + _M_index = __g._M_index; + return *this; + } + +_GLIBCXX_END_NAMESPACE + +#endif /* _GSLICE_H */ |
